基于NURBS最小二乘逼近的微段平滑加工算法

Micro sections adaptive interpolation algorithm based on NURBS least square approximation

在微段加工方式下,通常需要借助CAM(Computer Aided Manufacturing,计算机辅助)软件的后置处理将连续的加工路径离散化为大量微小直线段,并生成数控程序,数控系统则根据由微小直线段组成的加工路径进行插补和加工。但是,该方式具有加工程序量过大和需要频繁加减速来满足加工精度要求的两大不足。因此,为了实现微小直线段的高速平滑加工,提出了带权因子和一阶导数约束的NURBS曲线最小二乘逼近算法并加以了初步验证。算法的实质是将由微小直线段组成的加工路径拟合成一条连续的NURBS曲线,作为新的加工路径,然后利用NURBS实时插补对新的加工路径进行插补,实现微小直线段的高速平滑加工。经初步验证,算法有助于改善微段加工方式的加工质量和效率。

In the micro-segment processing method of tool path, the continuous tool path would be commonly dis- cretized into a series of micro sections by post-processing with the help of CAM （ Computer Aided Man- ufacturing） software, then micro sections are used to finish milling after the fine interpolating by CNC （ computerized numerical control）. But the faults of too large capacity of the NC files and frequent ac- celeration/deceleration control in the machining process are insuperably. Hence, a high-speed adaptive interpolation algorithm based on NURBS least square approximation is developed and tested. The key of the new algorithm is to approximate the micro sections into a NURBS curve as a new tool path, which can be interpolated easily by the NURBS interpolation algorithm. The test proved that, the new algo- rithm will improve the quality and efficiency of micro-segment processing.